The present invention relates to orthopedics, particularly to correcting abnormal head shape in infants, and to the treatment of torticollis.
The cranium of a human infant is made up of frontal, parietal, temporal, occipital and other smaller bones that are separated by membranous intervals until brain growth is complete at eighteen to twenty-four months of age. Normally, the infant cranium is symmetrical in shape. However, in the condition known as plagiocephaly, the head is non-symmetrical, becoming parallelogram or rhomboid shaped. Sometimes the plagiocephalic head may correct its shape over time, but often the condition may persist, leading to facial asymmetry with functional, cosmetic, and other disabilities. If orthotic treatment is indicated, it is important to attempt correction of the deformation when the subject is less than a year old, before the sutures in the cranium have solidified.
The shape of the infant cranium is determined by multiple factors including brain growth and development, constraints placed on the skull during and after gestation and bony abnormalities of the skull. When an infant""s head is maintained in a nearly fixed position either in utero or when sleeping on a flat surface, the cranium may be progressively deformed. A condition known as occipital positional plagiocephaly or deformational plagiocephaly frequently occurs in children who sleep in a relatively constant position on their backs. For example, as a result of the American College of Pediatrics recommendation that children be placed on their back instead of on their stomach to avoid SIDS (Sudden Infant Death Syndrome), a significant number of new cranial deformities are being seen (Argenta, L. C., et al., J. Craniofac. Surg. 7:5-11 (1996)). In addition, many infants have craniums that are deformed either in utero or during the birth process, and sleeping on the depressed portion of the skull accentuates the deformity. Infants who are slower to develop motor activity may also develop cranial abnormalities because of their failure to move their heads frequently. Finally, in some cases plagiocephaly is secondary to synostosis, a condition in which some of the skull sutures fuse too soon, making the skull bulge somewhere else.
Unfortunately, surgery is often the treatment prescribed to correct plagiocephaly of the infant skull. While plagiocephaly secondary to synostosis usually requires surgery, many deformities of the skull can be corrected with appropriate molding helmets (Argenta, L. C., et al., J. Craniofac. Surg. 7:5-11 (1996); Claren, S. K., et al., J. Pediatrics 94:43-46 (1979)). Such helmets take advantage of the pliability of the infant skull to mold the skull into a normal shape.
There are basically two types of corrective infant helmets. An active helmet is a device that places an active constricting force on the skull to force it to grow in a more normal fashion. These helmets are marketed as Dynamic Orthoplast Cranioplasty (DOC) helmets. In general, active DOC helmets must be custom fitted, require greater amounts of time for fabrication, and must be changed frequently as the infant head increases in size. As a result, DOC helmet therapy requires multiple clinic visits and may cost in the range of several thousands of dollars per patient. In addition, placing a constricting force on the growing brain is not thought to be physiological by most physicians.
Passive helmets or soft shell helmets attempt to take pressure off of the deformed portion of the skull, thus allowing the brain to grow in a more normal fashion. Thus, in contrast to active molding, passive helmets provide for a more gradual and physiological correction of skull shape.
A graded series of sized helmets for treatment of infant plagiocephaly were described in U.S. Pat. No. 4,776,324 to Claren. The Claren helmet is generated based on horizontal and transverse imaging measurements of either a patient skull or the skull of a normal infant. The Claren helmet fully encloses the head, and is designed such that it is slightly larger than the patient""s skull. The helmet uses passive molding in that the head grows into the helmet. A graded series of prefabricated helmets are required as an alternative to the previous technology using individualized helmets shaped to each patient""s skull.
Although full helmets are effective in treating plagiocephaly (Argenta, L. C., et al., J. Craniofac. Surg. 7:5-11 (1996)), they are confining and uncomfortable. Additionally, the use of several helmets is cumbersome and it can be difficult to match the individual patient""s skull with the prefabricated helmets available. Alternatively, the helmets which are generated based upon the patient""s individualized skull shape are expensive and time consuming to produce.
A cranial remodeling band using active molding to treat plagiocephaly is described in U.S. Pat. No. 5,094,229 to Pomatto. Pomatto described a cranial remodeling band with an internal surface which reflects the desired reconfiguration of the subject""s cranium. The technology employs active molding, in that it applies corrective forces to those regions of the cranium which protrude. The technology is expensive, however, in that effective therapy requires that the orthosis be individualized for each subject, and a series of helmets is required for each infant.
A helmet to correct brachycephalic cranial abnormalities is described in U.S. Pat. No. 5,308,312 to Pomatto. The brachycephalic head is expressed as an occipital flattening of the cranium such that the maximal cranial breadth is disproportionately large in relation to the maximum cranial length. The helmet described in U.S. Pat. No. 5,308,312 is designed to address a unique form of abnormal head shape. However, the helmet has many of the disadvantages of other helmets, e.g., for maximum effectiveness, the helmet must be fabricated from an impression of the individual subject""s head.
Thus, there is a need to develop corrective infant helmets that provide a gentle but effective therapy for the large majority of plagiocephalic infants. Rather than squeezing unaffected regions of the infant brain, it would be preferable to relieve the pressure from depressed areas of the skull. To enable correction of the abnormality before the brain plates begin to fuse, a helmet must be comfortable enough to be worn for the extended periods of time, up to 23 hours a day. In addition, such therapeutic helmets should be affordable and accessible to the many patients who require treatment.
The invention provides a helmet which, when worn by an infant, provides for a gentle reshaping of an infant""s skull. The helmet is a band to which a rounded, external protrusion is attached. By positioning the protrusion directly above an area on an infant""s head which is abnormally flat, the helmet encourages the infant to roll away from the flattened area, and to rest its head on a different region of the skull. The result is that pressure on the flat area of the skull is reduced, and pressure due to the weight of the infant""s head is directed elsewhere. Also, by providing a means for active positioning of the infant""s head, the helmet provides a means for treating neck abnormalities such as torticollis.
Thus, the invention provides in one aspect, a method and apparatus for treating plagiocephalic abnormalities of the infant cranium. The invention contemplates a helmet, which when worn by an infant with a plagiocephalic skull, forces the infant to turn his head away from a depressed portion of the skull and to lay upon regions of the head which protrude. In contrast to previous therapeutic methods, the disclosed invention employs both passive and active molding in that it passively relieves pressure from depressed areas of the skull while actively increasing pressure on areas of the skull which are distended.
The helmet comprises a pre-fabricated, adjustable first member that fits around an infant""s head, leaving a substantial portion of the patient""s upper cranium and ears exposed. In a preferred embodiment the first member comprises two discontinuous sections which overlap each other. The circumference of the first member may be adjusted by sliding the two sections of the first member together or apart. In addition, the first member is punctuated with apertures which provide ventilation, and if required, can be adapted for affixing fasteners. The first member should be strong enough to protect the infant""s head, but comfortable to wear. Thus, in a preferred embodiment, the exterior of the helmet comprises a high impact plastic and the interior of the helmet is lined with foam padding.
A substantially rigid convex second member is attached to the exterior of the first member and positioned directly above the depressed region on the infant""s skull. The second member is shaped so that when the infant rests it head upon a flat surface, the infant""s head rolls off of the second member and comes to rest on a different region of the skull. By adjusting the size and shape of the second member, abnormalities of varying size, shape and location may be selectively treated.
In another aspect, the invention relates to a method for the treatment of torticollis. Placing the second member on the same side of the head as those neck muscles which are affected forces the head to the side away from the torticollis. As the affected muscles become stretched and more relaxed, the second member can be progressively increased in size.
The foregoing focuses on the more important features of the invention in order that the detailed description which follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention which will be described hereinafter and which will form the subject matter of the claims appended hereto. It is to be understood that the invention is not limited in its application to the details of construction and to the arrangement of the components set forth in the following description and drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways.
From the foregoing summary, it is apparent that an object of the present invention is to provide a new and improved apparatus and method for the treatment of infant head and neck abnormalities. These, together with other objects of the present invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this document.